Ethanol and Acres

Dr. Pournelle,

I did some calculations on the acreage required to accomplish, inter alia, American energy independence WRT oil & natural gas imports, using sugarcane-derived ethanol & biodiesel from oil palms. I chose these crops because they have some of the highest fuel-per-acre yields - and hence the lowest land requirements - of all biomass crops. My results:

 

 

Required acreage using...
Amount of energy 	Oil palms 	Sugarcane
US gasoline consumption 	270,973,194 	351,817,804
US transportation fuel 	406,986,942 	528,411,132
US oil imports 	373,436,047 	484,850,358
US oil consumption 	602,457,373 	782,199,992
US oil & natural gas imports 	428,867,960 	556,820,333
US oil & natural gas consumption 	958,388,605 	1,244,322,989
US fossil fuel electricity 	409,904,411 	532,199,026
US fossil fuel consumption 	1,308,484,899 	1,698,870,200
World - Gulf oil exports 	622,815,277 	808,631,659
World - total oil consumption 	2,727,888,108 	3,541,751,089

 

Sources: here <http://www.eia.doe.gov/neic/quickfacts/quickoil.html>  for US gasoline consumption; here <http://eed.llnl.gov/flow/02flow.php>  for other US stats; here <http://www.eia.doe.gov/emeu/cabs/index.html>  for Persian Gulf oil exports; here <http://www.eia.doe.gov/neic/quickfacts/quickoil.html>  for world oil consumption; here <http://bioenergy.ornl.gov/papers/misc/energy_conv.html>  for various conversion factors; here <http://www.earth-policy.org/Books/PB2/PB2ch2_ss5.htm>  for per-acre oil palms & sugarcane yield

[I realize that Lester Brown is of dubious reliability, but his numbers for per-acre yields track with what I've read elsewhere.]

Since the yield-per-acre of corn-derived ethanol is little over half that of sugarcane-derived ethanol, using corn instead of sugarcane would almost double our land-use requirements.

By way of comparison:

* US farmland area: 938 million acres * US cropland area: 434 million acres * US harvested acreage: 303 million acres

(See here <http://www.ers.usda.gov/StateFacts/US.htm>  for source)

Based on these numbers, it appears that we could just barely achieve energy independence using sugarcane, or oil palms, or sugar beets. Provided we devoted the vast majority of currently-idle farmland to biofuels production.

In some cases - e.g., ethanol production from sugarcane or sugar beets - the use of biofuels really does amount to burning foodstuffs. But even in the case of non-food crops - e.g., oil palms, switchgrass - every acre of land used to cultivate biofuels is an acre of land that's not being used for food cultivation. Although some might argue that cultivating of biofuels only on currently-idle agricultural land would prevent biofuels from competing with foodstuffs for land, but this only works if food and energy demands both remain constant. Of course, energy consumption correlates with a growing economy, and food consumption with a growing population, so unless we're going to permanently restrict either type of growth, reliance on biofuels will eventually force food & fuel to compete for land.

As I believe you've noted before, only in the very limited case of burning, gasifying, or otherwise converting agricultural wastes does the use of biomass not amount to burning foodstuffs in one way or another.

FWIW, I'd prefer to see America concentrate on nuclear & space solar power. If, for whatever reason, we insist on using some sort of biofuel, algae biodiesel <http://oakhavenpc.org/cultivating_algae.htm>  seems the least worst option given its high yield-per-acre.

But then, I'm just an engineer with pretensions. What do I know?

Respectfully submitted,

Matthew Ing 

http://www.jerrypournelle.com/mail/mail463.html#Monday